Avoid Censorship Words Affect In Signature
 

Hi, currently, if we set censorship word, it will censor word in everywhere, postbit, PM, visitor profile & signature.

But, how do to make sure it will not work in signature ?

There's no way to do that with the censorship options, it works by doing a replace on the entire page just before it's sent to the user. I guess what you could do is look for one or more mods that let you censor posts, PMs, and visitor messages and use those instead.